Ethanol and corresponding feed co-products may be produced from a variety of feedstocks using any conventional dry mill or wet mill fermentation process known in the art. See for example, CORN, Chemistry and Technology, Stanley A. Watson and Paul E. Ramstad, editors, Published by the American Association of Cereal Chemists, Inc., St. Paul, Minn., USA, the entire contents of which are incorporated herein by reference.
Maximizing ethanol output is a concern for owners and operators of existing ethanol facilities. Thus, there exists a need for cost-effective measures that increase ethanol output from ethanol facilities, particularly from cereal based facilities.
Ethanol produced from fermentation of cereal grains yields co-products that are useful as animal feeds. Some of these feed co-products are known in the art as Wet Distiller's Grains (WDG), Dried Distiller's Grains (DDG), Wet Distiller's Grains Plus Solubles (WDGS), or Dried Distiller's Grains plus Solubles (DDGS). Removal of the starch component during fermentation concentrates the original protein, mineral, vitamin, fiber, and fat content. For example, dry mill ethanol production uses the starch portion of corn kernels, which is about 70% of the kernel. The starch component is converted by enzymatic hydrolysis to sugars which are then fermented to form ethanol. The ethanol is recovered by distillation. The remaining nutrients are concentrated into WDG or WDGS. The WDG or WDGS may be used directly as a feed co-product or may be dried to form DDG or DDGS. Drying increases shelf life and improves transportability.
Among the grain feed components, protein has the highest value commercially while fiber has the least value. Although the nutritional value of grain feed products may vary slightly according to its source (e.g., corn, sorghum (milo), sugar beets) and crop quality, these are essentially commodity products. Accordingly, a method for improving the quality and value (i.e., increased protein content and/or decreased fiber content) of grain feed co-products resulting from ethanol production is desirable to produce grain feed products having enhanced nutritional value as compared to the grain feed products currently available from the commodity markets.